Conventional wisdom says Trump sluiced through the fractious late 1960s relatively unmoved, shirt-and-tie focused on the family’s real estate business and trying to turn his father’s wealth into some of his own. Even now, at the start of his third year as president, and heading to Hanoi for his second summit with North Korean despot Kim Jong Un, conversations about Trump and Vietnam typically start and finish with how he skirted getting drafted, or what he said about John McCain, or perhaps his habit of likening his sexual promiscuity to the dangers of combat.

But over the years, as the United States as a whole struggled to move on from the psychological trauma of his generation’s signature conflict, Trump did not let go of Vietnam. In his invocations of the place, the war and its resonance as a fissure in modern American history, Trump has mined a rich and useful vein, presenting himself variously as charitable, virile, lucky and tough. But more than even that, Trump has deployed Vietnam as a bedrock tenet of his rudimentary worldview: We don’t win anymore.

“Weakness,” Tony Schwartz, who spent hundreds of hours with Trump while writing the words for "The Art of the Deal," told me, “is Trump’s greatest fear.” As such, in the estimation of Schwartz, the takeaway of the war in Vietnam was viscerally unsettling, “his worst fear writ large — that the enemy, with far less money and resources, would figure out a way to outwit the Goliath.” In this telling, the Goliath is the U.S., but Trump himself, too — and the humbling retreat in 1975 was not only a national wound, Schwartz suggested, but a personal affront. And over time he has turned that grievance into an appeal that clicked with a constituency that shared his frustration. “He is always trolling for sore spots, unresolved issues, places to egg on grudges and resentments,” biographer Gwenda Blair told me, “and Vietnam is no exception.”

“He’s a Nixonian culture wars guy.” — Historian Douglas Brinkley

Trump graduated from college at the utter apex of the war. The day of his 1968 commencement at the Wharton business school, at the University of Pennsylvania, 40 American soldiers were killed. That year would become the bloodiest of the war. More than half a million of his peers were fighting in Vietnam. Trump, 22, fit and strong, didn’t join them. He “wasn’t a fan of the Vietnam War,” and he also “wasn’t a marcher,” he hassaid. “I had other things to do.” He has often cited the fortune of a high draft lottery number, but that’s not the reason he didn’t go; the lottery didn’t even begin until December 1969. Trump didn’t go, like many men his age, because of four education deferments—and then, more consequentially, a medical deferment in the fall of ‘68 due to a sincemuch-discussed set of heel spurs. In any event, while a Princeton-educated lieutenant named Robert Swan Mueller III was leading a platoon of Marines in the thick of searing combat, Trump was back in his father’s office in Brooklyn, collecting rent and planning his move to Manhattan.

“Trump was AWOL from the Vietnam generation. He didn’t protest in the streets of America or go to Southeast Asia,” presidential historian Douglas Brinkley told me. This, however, Brinkley quickly added, did not mean Trump was unaware of what was happening. The country seemed to be cleaving into two, and President Richard Nixon remained popular at the time, and those two things were not unrelated. Trump is not a conservative in the mold of Ronald Reagan, said Brinkley, assessing his most important political influences. “He’s a Nixonian culture wars guy.”

And Vietnam, the war, its veterans and what citizens of this country thought of them or did or didn’t do for them became the crucible of those culture wars.

In the middle of the 1980s, in the wake of the career-making opening of Trump Tower, Trump co-chaired the New York Vietnam Veterans Memorial Commission and gave his time (albeit sporadically, somesaid) and money ($1 million) in the effort to build the city’s memorial along the East River. “I was a very strong opponent of the Vietnam War,” he told the Times at the dedication in May of 1985, “but I also recognized that the people who went to fight were great Americans. I always thought they got a bad shake in life and never got their just recognition.”

A decade later, though, on the Howard Stern Show, Trump compared that service and sacrifice with his post-divorces dating capers.

The danger of dating, he said in 1997, was the possibility of contracting a sexually transmitted disease. “My own personal Vietnam,” he explained. “I feel like a great and very brave soldier.”

Two years after that, when he was talking about running for president as a Reform Party candidate, Trump for the first time was asked about Vietnam in a specifically political context.

“Did you serve in the military,” Tim Russert asked him on “Meet the Press” in October of 1999.

“I did not.”

“What reason?”

“Well, I got very lucky. We had lottery numbers, and I guess this was my biggest factor of luck in my life …”

“The Vietnam War build-up in 1965,” Chris Matthews said to Trump the following month on MSNBC. “Would you have done that?”

“Vietnam was a disaster. It was too far away. It didn’t affect us" — Donald Trump

His blunt response in retrospect was an initial glimpse at two of the animating themes of his zero-sum foreign policy. Brawn. With a strain of isolationism. “Vietnam was a disaster,” Trump told Matthews. “It was too far away. It didn’t affect us. I guess if you do it, you have to go to win. We didn’t go to win. But I think Vietnam would have been a good place for us to stay out of.”

In 2005 and ’06, enjoying his spiking, "Apprentice"-amped celebrity and talking again to shock jocks instead of political pundits, Trump commented on America’s growing crisis in Iraq with additional references to Vietnam.

“Remember in Vietnam when we used to say, there used to be a certain group that would say, ‘Declare victory and leave?'” Trump told Don Imus. “Well, that sounds like one here — ‘declare victory and leave,’” he said, advocating essentially for the military version of a familiarTrumptactic.

“Iraq is the biggest disaster ever,” he said to Stern.

“Disaster?” Stern said.

“It’s making Vietnam look like a good war,” Trump said.

Finally, in 2008, in what now feels like a frivolous interlude, Miss Universe, which Trump at the time co-owned with NBC, held its annual pageant in Nha Trang, Vietnam. The winner was Miss Venezuela. Rounding out the top five were Miss Colombia, Miss Dominican Republic, Miss Mexico and Miss Russia. For the second straight year, during the evening gown portion of the competition, Miss USA slipped and fell. An ascendant Lady Gaga sang a song. Jerry Springer was one of the hosts. Donald Trump Jr. was one of the judges. His famous father, though, wasn’t there, later explaining to Stern that the plane flight was too long.

Donald Trump Jr. | Manny Carabel/Getty Images

It wasn’t until Trump started to really run for president that the primacy of Vietnam’s role in his life began to come into fuller focus. The ways he used it were revealing. “It’s not like he’s particularly interested in Vietnam as a country,” Charlie Laderman, a historian at King’s College London and one of the authors of the 2017 book, "Donald Trump: The Making of a World View," told me. “It’s something he’s able to utilize.”

First, he recalled on occasion his work on the memorial in New York. “Every time I see a vet, and especially a Vietnam vet, they say, ‘Mr. Trump, thank you for the memorial,’” he said at a rally in Iowa, for instance, six weeks into his candidacy. (That was exactly a week after he had said McCain was “not a war hero” and was considered one “because he was captured” but that he preferred people who “weren’t captured.”)

Second, and throughout his erratic but effective campaign, he cast Vietnam as the latest addition to the roster of countries taking advantage of the U.S. “Another one,” he said in a speech in Iowa. “A new one,” he said in South Carolina. “A new hot one,” he said in Connecticut.

More than anything else, though, he used the war in Vietnam and its sad, wrenching consequences to undergird the gut-level oomph of Make America Great Again.

"Vietnam was a loss. Nothing else you can call it. And then after that, we now — we don’t even think about winning." — Donald Trump

For Trump the setting and the stakes were new. The thought certainly was not. At New York Military Academy, the stern, upstate school he attended from eighth grade on, Trump imbibed the mantra of “in it to win it,” Peter Ticktin, one of his classmates, told me. That, Ticktin said, applied to Americans and America. “It was the feeling of supremacy that this country had in the 1950s,” Trump said to graduating students in a speech at Lehigh University in 1988. “It was a feeling of supremacy. It really was. And I had — I didn’t know it well — I was very young at that point — and I didn’t know the feeling of supremacy. I’ve known that since the Vietnam War …”

Now, though, as his bid for president built, he bored down on this idea.

“So,” he said in New Hampshire, “when I was young and went to school, I had always heard we never lost, this country, we never lost a war, you know, World War I, World War II, we — we just didn’t lose wars. And since then, I mean, when you think of it, you look at Vietnam …”

“Prior to Vietnam, we never lost a war, right?” he said in Tennessee. “Vietnam was a loss. Nothing else you can call it. And then after that, we now — we don’t even think about winning.”

As president, in addition to attackingonTwitter Senator Richard Blumenthal of Connecticut, whom he’s dubbed “Da Nang Dick,” Trump has hosted the Vietnamese prime minister at the White House, where he credited Nguyen Xuan Phuc with having “done a spectacular job.” This will be Trump’s second visit to Vietnam, where he’s more popular than he is at home. On his first visit, in November of 2017, he met again with Phuc and also met with some American veterans. They were, he said, “special, special people,” “great, great warriors” and “tough, smart cookies.”

“Like many of that era, he has been fixated on Vietnam ever since,” Trump biographer Michael D’Antonio told me this week. “Those who didn’t serve carry guilt and resentment over the feelings of guilt. Trump isn’t the type to get over anything let alone this issue.”

And he continues to process it in the way he processes nearly everything. “In a way,” added fellow biographer Blair, “it’s as if he’s an ongoing, one-man focus group, constantly trying things out and seeing how they play in terms of his own self-interest.”

What struck Laderman the most in his research for his book was the apparent lack of importance of ideals or values in the formation of Trump’s foreign policy and overall view of the world. With respect to Vietnam specifically, according to Laderman, what seemed to trouble Trump was not that the defeat was (as many conservatives saw it) a setback in the broader Cold War struggle or (as many liberals saw it) an undermining of America’s positioning as a global promoter of human rights. “It all really does,” Laderman said, “come back to power in a very naked sense.”